If the phenomenon of double infection was marginal since the start of the pandemic, the appearance of the Omicron variant changed the situation. In Quebec, the number of presumed reinfections has greatly increased since the arrival of the variant, reveals a report from the National Institute of Public Health of Quebec (INSPQ).
Reinfections peaked from December 26 to December 1er January ; they then represented 3.2% of cases. A month earlier, the double infection rate was rather 0.7%, more than four times less.
This outbreak, however, comes in the context of the records of positive cases recorded across the province during the same period, with an average of 15,595 daily cases.
A report from Imperial College London estimates that the risk of reinfection with the Omicron variant is 5.4 times greater than that of the Delta variant. Therefore, the protection conferred by prior infection against re-infection with the Omicron variant could be as low as 19%.
Less lethal
Despite the sharp increase in the number of people reinfected with the arrival of Omicron, the INSPQ has not observed an increase in their proportion among patients admitted to hospital or intensive care, nor an increase in deaths. .
Of all the cases of dual infection identified since the start of the pandemic, only 1% required hospitalization outside intensive care, and 0.2% died. Just under a quarter of those who were re-infected reported experiencing symptoms.
Reinfections have also affected young people more. Half of the second infections reported between December 26 and December 1er January were for 20-39 year olds and 30% for 40-59 year olds.
There are also 70 people who have contracted the virus three times.
The vast majority of suspected reinfections (83.8%) identified since May 23, 2020 occurred more than 150 days after the first infection.